Aplicação localizada de herbicidas para controle de alecrim-do-campo (Vernonia nudiflora) em pastagem natural.

Resumo: Para avaliar o controle de alecrim-do-campo (Vernonia nudiflora) com aplicação de herbicidas de contato, foi conduzido durante 353 dias, um experimento com delineamento de parcelas subdivididas, dispostas em blocos ao acaso, com três repetições em um arranjo fatorial (5x3)+1, sendo cinco herbicidas em três doses mais a testemunha. As parcelas corresponderam aos herbicidas, com doses de 1,5; 3,0 e 4,5 L ha-1 de Tordon, Aminol 806, Garlon, Grazon e Plenum. A abundância de V. nudiflora foi avaliada antes da aplicação e 60 e 353 dias após. A aplicação foi feita com ?roçadeira química? tratorizada, consistindo em uma plataforma com bandejas com altura regulável, que entra em contato somente com as plantas alvo. Os herbicidas não diferiram quanto à redução na abundância do alecrim e todos reduziram significativamente mais que a testemunha. Os tratamentos não interferiram na frequência na composição de espécies desejáveis no campo nativo. O uso do aplicador químico é eficaz para o controle, mesmo com baixas concentrações de herbicidas, tendo eficácia na redução do alecrim-do-campo e preservando as espécies desejáveis para a produção animal. [Located herbicide application to control alecrim-do-campo (Vernonia nudiflora) in natural grassland]. Abstract: To evaluate the control of alecrim-do-campo (Vernonia nudiflora) with contact herbicides, an experiment was conducted during 353 days, following a split plot block design, with three replicates in a (5x3)+1 factorial arrangement, being five herbicides in three doses and the control. The plots corresponded to the herbicides, with doses of 1.5, 3.0 and 4.5 L ha-1 of Tordon, Aminol 806, Garlon, Grazon e Plenum. The presence of V. nudiflora was evaluated prior to application and 60 and 353 days after. The application was made using a chemical applicator, which consists of a platform of adjustable height that contacts only the target plant. The herbicides did not differ in reducing the abundance of V. nudiflora and all of them reduced significantly more than the control. The chemical applicator was effective to control alecrim-do-campo, even with low herbicide concentrations, reducing the Vernonia abundance and not being harmful to the native desirable species

Controle de espécies indesejáveis e preservação de leguminosas de campo nativo com aplicação localizada de herbicidas.

Resumo: Para avaliar o efeito da aplicação localizada de herbicidas por contato, em Desmodium incanum, foi conduzido este estudo pelo período de 353 dias. O delineamento experimental foi de parcelas subdivididas, dispostas em blocos ao acaso, com três repetições em um arranjo fatorial [(5x3)+1], sendo cinco herbicidas mais a testemunha e três épocas de avaliação. As parcelas corresponderam aos herbicidas, locados na dose de 1,5 L ha-1 de Tordon, Aminol 806, Garlon, Grazon e Plenum, sendo compostas por oito quadros dispostos sobre uma transecta fixa. Realizou-se um levantamento prévio ao experimento, e dois levantamentos subseqüentes aos 60 e 365 dias apos a aplicação. A planta indesejável mais frequente era Vernonia nudiflora. Para aplicação dos herbicidas utilizou-se uma 'roçadeira química' tratorizada, consistindo em uma plataforma com bandejas com altura regulável, que entra em contato somente com as plantas alvo. O uso do aplicador químico foi eficaz para o controle de espécies indesejáveis além de não interferir na frequência do Desmodium incanum, sendo interessante a limpeza seletiva e preservação da flora nativa. [Weed control and preservation of native legumes species in natural grassland by herbicide localized application] Abstract: To evaluate the effect of localized application of herbicides by contact, in Desmodium incanum, this trial was conducted during a period of 353 days. The experimental design was a split plot arranged in a randomized block design with three replications in a factorial arrangement [(5x3) +1], five herbicides plus the control and three evaluation periods. The plots corresponded to herbicides, doses were locate: 1.5, 3.0 and 4.5 L ha -1 of Tordon, Aminol 806, Garlon, Grazon e Plenum, being composed by 8 tables arranged on a fixed line. Prior to application, was made a survey, another in 60 and 353 days after application. For the herbicides application, was used a chemical applicator, which consists in an adjustable height platform, and it is contact is only with the target plant. The use of chemical applicator was effective for controlling undesirable species besides not interfere on Desmodium incanum frequency besides being interesting for selective cleaning and preservation of the native vegetation

Deslocamento e estimativa de gasto energético de ovinos manejados com diferentes métodos de pastoreio e ofertas de forragem em campo natural

The Trial was conducted at an 8.4ha natural grassland area, subdivided into 12 experimental units of 0.7 each in the Universidade Federal do Rio Grande do Sul, when were tested two grazing methods (continuous and rotational(CS and RS) and two herbage allowances (HA; 12 and 18 kg dry matter/100 kg live weight; 12 and 18%), resulting in four treatments: CS12, CS18, RS12 and RS18. The displacement was measured during a 24h period using GPS devices fixed on the ewes back. Together with this evaluation was made a grazing behavior evaluation to synchronize the displacement with the grazing activity. With the GPS data (total and grazing displacement) the energy expenditure was predicted using equations reported in the literature. The herbage allowance did not influence the displacement and the estimations of energy expenditure. The CS presented a higher displacement than RS. Under the assumptions of estimations of energy expenditure, a higher level along all day and during grazing would be expected in the CS. Depending of the pasture quality, variations in the grazing methods could become an important management tool.O ensaio foi conduzido em 8,4ha de campo nativo, dividido em 12 unidades experimentais com 0,7ha, testando dois métodos de pastoreio (lotação contínua e rotativa; LC e LR) e duas ofertas de forragem (12 e 18 kg MS/100 kg PV; 12 e 18%) com ovelhas em gestação, gerando quatro tratamentos: LC12, LC18, LR12 e LR18. Foram medidos os deslocamentos durante um período de 24h utilizando-se aparelhos de GPS fixado na região das cruzes dos animais e o deslocamento na atividade de pastejo e procura de alimento, por meio de sincronização dos dados dos GPS e comportamento ingestivo, qual foi avaliado na ocasião. Com os deslocamentos medidos os gastos energéticos foram estimados por meio de formulas matemáticas repostadas na literatura. As OF não modificaram o deslocamento dos animais durante 24 horas ou em pastejo. O deslocamento só foi influenciado pelos métodos de pastoreio, onde os animais sob lotação contínua se deslocaram mais. Assumindo as estimativas de gasto energético, um alto nível de gasto durante o dia e na atividade de pastejo é observada no método contínuo. Dependendo da qualidade da pastagem, variações no método de pastoreio podem se tornar importantes ferramentas de manejo

Controle de espécies indesejáveis e preservação de leguminosas de campo nativo com aplicação localizada de herbicidas

To evaluate the effect of localized application of herbicides by contact, in Desmodium incanum, this trial was conducted during a period of 353 days. The experimental design was a split plot arranged in a randomized block design with three replications in a factorial arrangement [(5x3) +1], five herbicides plus the control and three evaluation periods. The plots corresponded to herbicides, doses were locate: 1.5, 3.0 and 4.5 L ha -1 of Tordon, Aminol 806, Garlon, Grazon e Plenum, being composed by 8 tables arranged on a fixed line. Prior to application, was made a survey, another in 60 and 353 days after application. For the herbicides application, was used a chemical applicator, which consists in an adjustable height platform, and it is contact is only with the target plant. The use of chemical applicator was effective for controlling undesirable species besides not interfere on Desmodium incanum frequency besides being interesting for selective cleaning and preservation of the native vegetation.Para avaliar o efeito da aplicação localizada de herbicidas por contato, em Desmodium incanum, foi conduzido este estudo pelo período de 353 dias. O delineamento experimental foi de parcelas subdivididas, dispostas em blocos ao acaso, com três repetições em um arranjo fatorial [(5x3)+1], sendo cinco herbicidas mais a testemunha e três épocas de avaliação. As parcelas corresponderam aos herbicidas, locados na dose de 1,5 L ha-1 de Tordon, Aminol 806, Garlon, Grazon e Plenum, sendo compostas por oito quadros dispostos sobre uma transecta fixa. Realizou-se um levantamento prévio ao experimento, e dois levantamentos subseqüentes aos 60 e 365 dias apos a aplicação. A planta indesejável mais frequente era Vernonia nudiflora. Para aplicação dos herbicidas utilizou-se uma “roçadeira química” tratorizada, consistindo em uma plataforma com bandejas com altura regulável, que entra em contato somente com as plantas alvo. O uso do aplicador químico foi eficaz para o controle de espécies indesejáveis além de não interferir na frequência do Desmodium incanum, sendo interessante a limpeza seletiva e preservação da flora nativa

Aplicação localizada de herbicidas para controle de alecrim-do-campo (vernonia nudiflora) em pastagem natural

To evaluate the control of alecrim-do-campo (Vernonia nudiflora) with contact herbicides, an experiment was conducted during 353 days, following a split plot block design, with three replicates in a (5x3)+1 factorial arrangement, being five herbicides in three doses and the control. The plots corresponded to the herbicides, with doses of 1.5, 3.0 and 4.5 L ha-1 of Tordon, Aminol 806, Garlon, Grazon e Plenum. The presence of V. nudiflora was evaluated prior to application and 60 and 353 days after. The application was made using a chemical applicator, which consists of a platform of adjustable height that contacts only the target plant. The herbicides did not differ in reducing the abundance of V. nudiflora and all of them reduced significantly more than the control. The chemical applicator was effective to control alecrim-do-campo, even with low herbicide concentrations, reducing the Vernonia abundance and not being harmful to the native desirable species.Para avaliar o controle de alecrim-do-campo (Vernonia nudiflora) com aplicação de herbicidas de contato, foi conduzido durante 353 dias, um experimento com delineamento de parcelas subdivididas, dispostas em blocos ao acaso, com três repetições em um arranjo fatorial (5x3)+1, sendo cinco herbicidas em três doses mais a testemunha. As parcelas corresponderam aos herbicidas, com doses de 1,5; 3,0 e 4,5 L.ha-1 de Tordon, Aminol 806, Garlon, Grazon e Plenum. A abundância de V. nudiflora foi avaliada antes da aplicação e 60 e 353 dias após. A aplicação foi feita com “roçadeira química” tratorizada, consistindo em uma plataforma com bandejas com altura regulável, que entra em contato somente com as plantas alvo. Os herbicidas não diferiram quanto à redução na abundância do alecrim e todos reduziram significativamente mais que a testemunha. Os tratamentos não interferiram na frequência na composição de espécies desejáveis no campo nativo. O uso do aplicador químico é eficaz para o controle, mesmo com baixas concentrações de herbicidas, tendo eficácia na redução do alecrim-do-campo e preservando as espécies desejáveis para a produção animal

Use of \u3cem\u3eN\u3c/em\u3e-Alkane Technique to Estimate Sheep Dry Matter Intake

Given the complexity of evaluating intake on grazing, some compounds have been studied to promote qualitative and quantitative estimates of animal physiology. In this sense, the technique using n-alkanes as a marker has been used in several animal species, especially in grazing ruminants (Dove and Mayes 1996). By definition, validation under grazing or browsing conditions is not possible, because actual intakes are unknown (Dove and Mayes 2005). Thus, the aim of the study was to evaluate the methodology of n-alkanes to estimate herbage intake by sheep in metabolic cages

Visible photodissociation spectroscopy of PAH cations and derivatives in the PIRENEA experiment

The electronic spectra of gas-phase cationic polycyclic aromatic hydrocarbons (PAHs), trapped in the Fourier Transform Ion Cyclotron Resonance cell of the PIRENEA experiment, have been measured by multiphoton dissociation spectroscopy in the 430-480 nm spectral range using the radiation of a mid-band optical parametric oscillator laser. We present here the spectra recorded for different species of increasing size, namely the pyrene cation (C16H10+), the 1-methylpyrene cation (CH3-C16H9+), the coronene cation (C24H12+), and its dehydrogenated derivative C24H10+. The experimental results are interpreted with the help of time-dependent density functional theory calculations and analysed using spectral information on the same species obtained from matrix isolation spectroscopy data. A kinetic Monte Carlo code has also been used, in the case of pyrene and coronene cations, to estimate the absorption cross-sections of the measured electronic transitions. Gas-phase spectra of highly reactive species such as dehydrogenated PAH cations are reported for the first time

Desempenho de ovelhas e cordeiros manejados com diferentes métodos de pastoreio e ofertas de forragem em campo natural

The objective of was to determine the influence of grazing methods with a relatively low or high herbage allowance in the first 84 gestation days on ewes/lambs daily weight gain (DWG) and area production. The study was conducted at an 8.4 ha natural grassland in South Brazil. During the winter, early pregnancy ewes were submitted to two grazing methods (continuous (CS) and rotative (RS) stoking) and two herbage allowances (HA; 12 and 18% live weight)), resulting in four treatments: CS18, CS12, RS18 and RS12. It was measured the DWG and body condition score (BCS) from ewes and from ewes and lambs after born, as well lambs area production. During the winter only the HA change the DWG from the ewes. During the spring differences were found only in the lambs DWG from grazing method, been higher in CS. A grazing method × HA interaction indicate that the higher lambs area production was achieved in the CS12 treatment. The results indicate that the grazing methods and HA had a little influence in the animal performance over winter and the herbage could be better used in this period.O objetivo foi determinar a influência dos métodos de pastoreio com uma relativa baixa e alta oferta de forragem nos primeiros 84 dias de gestação no desempenho de ovelhas e seus cordeiros após o nascimento. O trabalho foi conduzido em 8,4 ha de campo natural, quando os animais foram submetidos a diferentes métodos de pastoreio (lotação contínua (LC) e rotativa (LR)) e ofertas de forragem (OF, 12 e 18% do peso vivo (PV)), gerando quatro tratamentos: LC12, LC18, LR12 e LR18. Foi medido o ganho médio diário (GMD) das ovelhas e cordeiros e a condição corporal das ovelhas assim como a produção de cordeiros por área. No inverno o GMD somente foi modificado pelas OF. Na primavera, somente o GMD dos cordeiros apresentou efeito e somente para métodos de pastoreio, sendo o melhor desempenho encontrado nos cordeiros nascidos de ovelhas manejadas no inverno sob LC. Uma interação métodos × OF indicou que a maior produção por área de cordeiros foi no obtida em LC12. Os resultados indicam que os métodos de pastoreio e as OF tem pouca influência no desempenho animal no inverno e pode-se fazer uma melhor utilização da forragem neste período

The unusual protoplanetary disk around the T Tauri star ET Cha

We present new continuum and line observations, along with modelling, of the faint (6-8) Myr old T Tauri star ET Cha belonging to the eta Chamaeleontis cluster. We have acquired HERSCHEL/PACS photometric fluxes at 70 mic and 160 mic, as well as a detection of the [OI] 63 mic fine-structure line in emission, and derived upper limits for some other far-IR OI, CII, CO and o-H2O lines. The HERSCHEL data is complemented by new ANDICAM B-K photometry, new HST/COS and HST/STIS UV-observations, a non-detection of CO J=3-2 with APEX, re-analysis of a UCLES high-resolution optical spectrum showing forbidden emission lines like [OI] 6300A, [SII] 6731A and 6716A, and [NII] 6583A, and a compilation of existing broad-band photometric data. We used the thermo-chemical disk code ProDiMo and the Monte-Carlo radiative transfer code MCFOST to model the protoplanetary disk around ET Cha. Based on these models we can determine the disk dust mass Mdust = (2.E-8 - 5.E-8) Msun, whereas the total disk gas mass is found to be only little constrained, Mgas = (5.E-5 - 3.E-3) Msun. In the models, the disk extends from 0.022 AU (just outside of the co-rotation radius) to only about 10 AU. Larger disks are found to be inconsistent with the CO J=3-2 non-detection. The low velocity component of the [OI] 6300A emission line is consistent with being emitted from the inner disk. The model can also reproduce the line flux of H2 v=1-0 S(1) at 2.122 mic. An additional high-velocity component of the [OI] 6300A emission line, however, points to the existence of an additional jet/outflow of low velocity (40 - 65) km/s with mass loss rate ~1.E-9 Msun/yr. In relation to our low estimations of the disk mass, such a mass loss rate suggests a disk lifetime of only ~(0.05 - 3) Myr, substantially shorter than the cluster age. The evolutionary state of this unusual protoplanetary disk is discussed.Comment: accepted by Astronomy & Astrophysics (18 pages, 11 figures and 7 tables). Additional 9-page appendix with 6 figures, 3 tables and 37 equation

ISM properties in low-metallicity environments I. mid-infrared spectra of dwarf galaxies

We present new ISOCAM mid-infrared spectra of three starbursting nearby dwarf galaxies, NGC1569, IIZw40, NGC1140 and the 30Dor region of the LMC and explore the properties of the ISM in low-metallicity environments, also using additional sources from the literature. We analyse the various components of the ISM probed by the mid-infrared observations and compare them with other Galactic and extragalactic objects. The MIR spectra of the low-metallicity starburst sources are dominated by the [NeIII] and [SIV] lines, as well as a steeply rising dust continuum. PAH bands are generaly faint, both locally and averaged over the full galaxy, in stark contrast to dustier starburst galaxies, where the PAH features are very prominant and even dominate on global scales. The hardness of the modeled interstellar radiation fields for the dwarf galaxies increases as the presence of PAH band emission becomes less pronounced. The [NeIII]/[NeII] ratios averaged over the full galaxy are strikingly high, often >10. Thus, the hard radiation fields are pronounced and pervasive. We find a prominent correlation between the PAHs/VSGs and the [NeIII]/[NeII] ratios for a wide range of objects, including the low metallicity galaxies as well as Galactic HII regions and other metal-rich galaxies. This effect is consistent with the hardness of the interstellar radiation field playing a major role in the destruction of PAHs in the low metallicity ISM. We see a PAHs/VSGs and metallicity correlation, also found by Engelbracht et al. (2005) for a larger survey. Combined effects of metallicity and radiation field seem to be playing important roles in the observed behavior of PAHs in the low metallicity systems.Comment: accepted by A&